In this paper, we have studied the information paradox in the context of Schwarzschild de-Sitter black hole spacetime, using Island proposal, where we have introduced a thermal opaque membrane to isolate the black hole from the de-Sitter patch on both sides and vice-versa. We have computed the entanglement entropy of Hawking radiation in the absence and presence of island surface and found that as usual entanglement entropy has linear time dependence when there is no island surface whereas entanglement entropy becomes constant in the presence of island surface. Therefore, we obtain the Page curve consistent with the unitary evolution of the black holes. In our case, island is located inside the black hole horizon in comparison to universal result that island is located outside the horizon for eternal black holes [1]}. However, for the eternal black holes the aforementioned problem can be solved by quantum focusing conjetcure (QFC) [2]}. Due to QFC, when we decouple or couple a black hole to bath, then finite amount of produced energy flux shift the horizon outward without affecting the location of island surface and hence island always lies inside the black hole horizon. Our result is also similar to [3]}, where authors computed the Page curve of one-sided asymptotically flat black hole and discovered that the island is located inside the horizon.
